Proverbs 1:18- And they lay wait for their own blood; they lurk privily for their own lives.
Verse after verse now, we are warned of the unruly. This verse teaches us a simple way of identifying someone that would do us harm, it is in that they do themselves harm. Remember we are taught in God's word to love each other as we would love our own selves. If one does not love but harm themselves, it's best to not get entangled with that person. The key word in the previous sentence is "entangled". Perhaps you meet someone who is inflicting self harm and shows a desire to repent. By all means, if you see an avenue to help, that would be the Godly thing to do. However, if the person is inflicting self harm and does not care to repent, to yoke up with that person could bring destruction upon you. I bring you back to verse 10, My son, if sinners entice thee, consent thou not. May God then guide us, on when to help somebody and when to avoid.
In Christ